The relationship between growth fractions and oestrogen receptors in human breast carcinoma, as determined by immunohistochemical staining.

Measurements of the growth fraction (GF) and oestrogen receptor (OR) status were performed by immunohistochemical staining, using the monoclonal antibodies Ki-67 and anti-OR, in consecutive cryostat sections of biopsies from 74 women with primary breast cancer, and 12 women with benign breast disease. A significant inverse correlation was identified between the GF and OR status (r = -0.452, P less than 0.0001), but a group of OR-positive tumours with high GFs was also observed. There was a strong positive correlation between immunocytochemically determined OR percentages and values obtained with a cytosolic OR biochemical assay for the 70 cases in which both techniques were performed (r = 0.801, P less than 0.0001). A significant relationship was also revealed between the histological grade of infiltrating ductal carcinomas and their associated GFs (r = 0.622, P less than 0.0001). No correlation was found between the GF and the number of positive axillary nodes. Our findings suggest that GF and OR status are useful independent prognostic parameters in breast cancer, but the former probably has an overriding influence. Both parameters may be useful guides for selection of appropriate endocrine and/or adjuvant chemotherapy.